1. Field
Aspects of the present invention relate to a protection circuit of a battery pack, the protection circuit detecting the error of a charging device in the battery pack.
2. Description of the Related Art
Recently, as portable apparatuses such as a mobile telephone, a portable audio apparatus, and a digital camera are widely used, use of a secondary battery is rapidly increasing. The secondary battery is portable since the secondary battery has high stability and is small and thin in size.
As a method of charging the secondary battery, a constant current-constant voltage (CC-CV) charging method is used. In the CC-CV charging method to charge the secondary battery, after charging is performed by a uniform constant current, charging is performed by a constant voltage corresponding to a voltage reaching a predetermined voltage, such as a voltage close to a full charge potential of the secondary battery.
In addition, as another method of charging the secondary battery, a pulse charging method disclosed in the U.S. Pat. No. 4,736,150 is used. In the pulse charging method, a pulse in the range between 0.1 to 10 Hz is applied at intervals between 1 ms and 9 ms so that the secondary battery is charged. When the pulse charging method is used, the correctness of the full charge is higher than in the CC-CV charging method.